Process for the production of wash-and-wear characteristics in woven fabrics of regenerated cellulose



re rate atent PROCESS FOR THE PRODUCTION OF WASH-AND= WEARCHARACTERISTISS IN WGVEN FABRICS OF REGENERATED CELLULOSE Bruno StefanVladimir Marek, Emmenbruclre, and Andre Michel Keller, Geneva,Switzerland, assignors to Societe de la Viscose Suisse, Emmenbrucke,Switzerland, a body corporate of Switzeriand N Drawing. Filed Feb. 11,1960, Ser. No. 7,993

Claims priority, application Great Britain Feb. 19, 1959 Claims. (Cl.28-76) This invention relates to the production of a drip-dry finish onwoven fabrics of regenerated cellulose.

According to the present invention there is provided a process for theproduction of a drip-dry finish, which is fast to washing, on fabrics ofregenerated cellulose which comprises immersing the fabrics in theabsence of a catalyst, in an aqueous solution of ethylenediamine of 70to 90% by Weight strength, allowing the ethylenediarnine to remain incontact with the fabric for 3 to- 30 minutes, removing theethylenediamine and drying the fabric during or after the removal of theethylenediamine.

The enthusiastic reception which textile materials made of man-madefibres have found with the public was mainly due to the fact thatfabrics made from such fibres and apparel made therefrom need no ironingor at most a minimum amount of ironing after washing to make them againready for Wear. This outstanding property is substantially due to threefactors, namely (a) reduced creasing tendency in the wet state or, moreprecisely, ready recovery from any creasing while wet, combined withwashresistance of any intentional creases previously produced bypressing or ironing; (b) ability to dry quickly, though some of thisability is also due to the structure of the fabric and the yarn, andabove all to reduced water absorption and swelling; (c) dimens onalstability, that is to say at most a minimum susceptibility to stretchingor shrinking during a wet treatment and drying respectively.

Attempts have, therefore, been made to impart an identical, so-calleddrip-dry, finish also to classic textile fibres, above all to cotton, bya suitable improving treatment, that to say by dressing them withsynthetic resins or by modifying the cellulose. Subsequently, it was anobvious step to try to produce the results obtained on cotton also onfibres of regenerated cellulose, but hitherto this has been found to berather ditficult owing to the differcnces between native cellulose andregenerated cellulose.

Moreover, the hitherto known processes for imparting a drip'dry finishto cellulose fibres involve considerable disadvantages, In the firstplace the drip-dry finish obtained on cellulose by chemical modificationis by itself insufficient and the finish obtained by dressing with asynthetic resin is not sufiiciently resistant to washing since theeffect diminishes with every successive Wash and disappears completelyafter about 20 to 30 Washes. Moreover, to achieve a satisfactorydiminution of swelling, 1

the amount of these synthetic resins applied to the fibre must be solarge that, on the one hand, the cost of the treated fabric is increasedsubstantially and, on the other hand, the treated fabric becomes stiff,which in turn impairs certain mechanical properties of the fibre,particusaid shortcomings. The treatment according to the invention doesnot impair, but rather improves, the mechanical properties; no chlorineretention occurs, and the dripdry finish produced on the fabric isenhanced, not reduced, by successive washes.

Several processes have been described for treating textiles withnitrogenous organic bases, more especially amines, with a view tomodifying certain properties of the textile material. In the firstplace, the present invention differs from those known processes in whicha genuine chemical reaction between the amine and the cellulose takesplace so that nitrogenous substitution products of cellulose are formed.Processes of this type generally require high temperatures and pressuresand aim as a rule at an animalisation of the fibre to increase itsaffinity for acid dyestuffs. Since the regenerated cellulose treated bythe present process does not contain any nitrogen, the aforementionedprocesses do not come within the scope of the present invention,

On the other hand, as far back as 1931, C. Trogus and K. Hess stated ina report on X-ray examinations of cellulose derivatives (Zeitschriftfilr physikalische Chemie, Part B, volume 14, pages 387-395) that whennative or hydrated cellulose is treated with a concentrated aqueoussolution of hydrazine or an alkylenediamine, the lattice of celluloseundergoes certain changes above a certain limit concentration, in thecase of ethylenediamine, for example, a concentration of the order of38-42%.

The authors stated that by such a treatment adducts of an.

unknown type are apparently formed which in contact With water arebroken down again. Whether after such a breakdown the changes that hadinitially occurred in the cellulose lattice persist or not, was notreported.

Subsequent researches concerned the question of whether cotton, afterhaving been treated with a solution of an amine, was more suitable forbeing dressed with resins.

British patent specification No. 479,341 described a process fortreating regenerated cellulose with amines, for example with an ethylenediamine solution of 55-65% strength, the swelling action of whichimproves the affinity of the fibre for cotton dyestuffs. According tothat publication the treatment is performed during or immediately priorto the dyeing process, in either case without intermediate drying. Theprocess of British patent specification No. 479,341 is particularlysuitable for treating regenerated cellulose manufactured by hydrolysinga cellulose ester, for example acetyl-cellulose. It is known that suchproducts have a very low dyestufi aifinity, while cellulose regeneratedby the viscose or cuprammonium processes has so high an affinity that itis unnecessary or even undesirable to increase it any further.

In British patent specification No. 683,203 it is proposed to impregnatecord filaments of regenerated cellu' lose with a primary amine toimprove their heat stability. British patent specification No. 750,088describes a process for reducing the water absorption of regeneratedcellulose, wherein vapours of alkylamines, hydrazine hydrate or ammoniagas are caused to act upon the moist fibre, advantageously under apressure of 1. to 5 atmospheres (gauge). Finally, in British patentspecifications Nos. 767,810 and 767,811 it is stated that the mechanicalstrength, stretchability and resistance to abrasion of cotton materialscan be improved by treating the material in the stretched state with anamine, such as ethylene diamine and more especially a 3-substitutedpropylamine.

None of the aforementioned processes involves the essential features ofthe present invention which are that the material treated must beregenerated cellulose material (not cotton), the treatment agent mustnecessarily be ethylenediamine and not any other alkylene diamine, thefabric must be immersed in the solution, the solution must contain 6590%by weight of ethylenediamine, and after the treatment theethylenediamine must be removed and the fabric dried during or aftersuch removal. Applicants have found that only by adherence to thesecondi- 'tions is the characteristic finish imparted to the fabric.

The present invention is based on the observation that fabrics ofregenerated cellulose undergo a peculiar change on being immersed merelyin a solution of ethylenediamine of a suitable concentration by becomingstrikingly soft, supple and slack. Compared with the handle imparted toa comparable untreated fabric by immersion in water, which may but neednot contain a detergent, the change produced is particularly surprising.Even more surprising is, however, the fact that this change (providedthe fabric is immersed for an adequate length of time) persists fullyeven after removing the ethylene diamine and washing and drying thefabric, although on being analysed the cellulose does not reveal anychange having taken place in it. When the fabric is subsequently wettedor washed with water, the soft handle persists and in addition it isobserved that any creasing that has occurred in wetting or duringwashing substantially disappears again in the following dryingoperation.

Thus, the change brought about by ethylenediamine is irreversible. Thefabric retains its newly acquired properties through repeated washes,even when it is washed twenty to fifty times; actually, these propertiesare even enhanced by Washing. So far it has not been possible to find atenable explanation for this observation. Is is also noteworthy thatthis phenomenon occurs only on regenerated cellulose but is practicallyabsent from untreated or mercerized cotton, that is to say nativecellulose.

Nor was it possible to obtain an identical effect by an analogoustreatment with other amines. Moreover, most of the other amines areunsuitable for the industrial performance of the present process becausethey are either too costly or give off offensive smells or vapours orare connected with other inconveniences.

It will be realised that in the application of this treatment process tothe production of a drip-dry finish several factors require specialattention. As has been mentioned above, the concentration of the aqueousethylenediamine solution plays a special role. It has been observed thatany concentration above or below the limit range of 70% to 90% iscapable of rapidly impairing the effect achievable by the presentprocess.

It will be realised that the temperature and the time for which theethylene diamine is allowed to act on the fibre likewise have a decisiveinfluence on the ultimate effect. On the other hand, it has beenobserved that optimum temperature and optimum time of treatment aredependent on the concentration of ethylene diamine and on the fibrestructure of the cellulose material under treatment and therefore mustbe adjusted for each specific treatment process.

A simple way of performing the treatment with the ethylene diamineconsists, for example, in immersing the dry and desized fabric in theethylene diamine solution, then expressing the fabric in any desiredmanner, for example between two rolls, washing the ethylene diamine outof it with water, if necessary neutralising the fabric with acetic acid,and finally drying it.

According to an advantageous variant of the process the fabric isimmersed in the ethylenediamine solution for a short time only, theexcess liquor is expressed, and the impregnated fabric is maintained fora specific time with the ethylenediamine present on it; during thisoperation it must be ensured that the heat released by the exothermicreaction does not reach the fabric. The fabric is then washed free fromet-hylenediamine, if necessary neutralised, and finally dried.

According to another variant the fabric is immersed in the ethylenediamine solution, expressed, and then continuously passed over rollsthrough a closed chamber in which the bulk of the ethylenediamineremaining in the fabric is evaporated at an elevated temperature; theethylene diamine can be recovered in a simple manner, and the reactionheat is compensated by the cold resulting from the evaporation of theethylene diamine. As in the other variants mentioned above, the fabricis then washed free from ethylenediamine and finally dried.

In experiments conducted with the present process it has been observedthat optimum results are achieved by working at a temperature notexceeding room temperature and advantageously with cooling, that is tosay at a temperature ranging from 0 to 20 C., and that even at animmersion temperature of 40 C. a distinct diminution in the anti-creaseeffect is noticeable. Furthermore, it has proved advantageous to washout the ethylenediamine in the cold, that is to say with water at 0 to10 C. to compensate for the heat of hydration released by the dilutionof the ethylenediamine remaining in the fabric. Furthermore, it has beenobserved that, quite generally, an immersion time below 3 minutes doesnot produce any appreciable effect while, on the other hand, immersionprolonged beyond 30 minutes does not improve the effect. In thisconnection a distinction must be made between the variant of thetreatment in which the fabric is actually immersed for 3 to 30 minutes,and the alternative variants wherein the immersion is followed by anadditional time of contact. In these latter cases immersion may last foronly 30 seconds, provided the expressed fabric remains in contact withthe ethylenediamine for a further period so that the total contact timeis at most 30 minutes. Furthermore, determination of the extent ofswelling has elicited the fact that in the case of highly orientedfibres of regenerated cellulose, of the type known by the namePolynosics, such as can be manufactured, for example, by the processesaccording to British specifications Nos. 650,896, 652,645 and 678,335 or720,173 and as described in the journal Rayonne, Fibranne et FibresSynthetiques, volume 9 (1959), page 531, the be ance betweenethylenediamine and cellulose in the treatment liquor is establishedsomewhat more rapidly than in the case of ordinary fibres of regeneratedcellulose. On fabrics of cellulose fibres of this type the effectproduced by the ethylenediamine treatment is particularly pronounced.

A fabric treated with ethylenediarnine by the present process, afterhaving been washed and drip-dried, displays an anti-crease resistance inthe wet state or a degree of recovery respectively which, as determinedby the Monsanto method and by the method described in SVF Fachorgan furTextilveredlung, volume 13 (1958), pages 247257 by Dr. B. S. Marek, Uberdie Beurteilung des Wash-and-Wear Charakters von Geweben durch Knitter-'bilder, corresponds to create pattern value 4 to 5, the value 5 in bothmethods being defined as the possible optimum.

It had not previously been known that such values could be obtained onstaple fibres of regenerated cellulose which in accordance with theirnature are particularly sensnrve to creasing in the wet state.

As mentioned above a satisfactory drip-dry finish on a fabric is notexclusively determined by the recovery from creasing in the wet state.Factors that must be taken into consideration at the same time are thespeed at which the fabric dries, that is to say above all reducedswelling tendency, adequate dimensional stability, as well as adequateresistance to creasing when dry and, of course, also satisfactorymechanical strength.

Though the swelling tendency is distinctly diminished by the ethylenediamine treatment, such diminution does not reach a degree such as isdesirable in drip-dry textiles. However, such a degree is easy toachieve by a suitable after-treatment as described hereinbelow.

Somewhat more difiicuit is the determination of the effect which theethylenediamine treatment has on the dimensional stability. It has beenobserved that dimensional stability is influenced, on one hand, by thetemperature prevailing during the ethylenediamine treatment, washing anddrying and, on the other hand, primarily by the fact of whether thefabric is under tension or not during the treatment with ethylenediamineor during the washing or drying. e difference is most noticeable withfabrics dried with and without tension respectively: when a fabric driedin stentered state is subsequently wetted or washed, it undergoesshrinking, while the fabric dried in the loose state undergoeselongation. Moreover, the fact of whether the fabric is under tension ornot during the treatment at the same time influences the property ofrecovery from creasing and the mechanical strength values. It can beshown that the resistance to abrasion can be affected to a certainextent by drying the fabric in the stentered state, while this has nodecisive effect on the recovery from creasing.

Quite generally, it may be said that it is of advantage to perform thewhole of the ethylenediamine treatment that is to say the immersion,optional contact with ethylenediamine solution in the expressed state,washing and dryingwith a minimum of tension. The dimensional stabilityof the fabric treated with ethylenediamine is however not substantiallybetter than that of the untreated fabric and is as such not entirelysatisfactory for drip'dry fabrics.

According to a further feature of the present invention regeneratedcellulose fabric treated with ethylenediamine in the manner describedabove is subjected to an after treatment to improve the afore-saidproperties, the after treatment being selected from the following:treatment with formaldehyde, compressive mechanical shrinking, orincorporation -or application of resins (if desired by condensation onthe fabric). The following examples will serve to illustrate theinvention:

Example I This example shows the effect of the ethylenediaminetreatment, performed by itself or in combination with a subsequentcompressive shrinking operation, on the recovery from creasing, themechanical strength and the swelling. The fabric used in this examplewas a calico fabric (linen weave) weighing 136 grams per sq. m.,consisting of 31 filaments of Ne 40/1 per cm. in the warp and 37filaments of Ne 40/1 per cm. in the weft and produced from viscosefibres of 7.5 deniers having a staple length of 38 mm.; the fabric wasimmersed for 5 minutes at room temperature in a commercial aqueoussolution of ethylenediamine of 86.5% strength and then expressed to aweight increase of 100%, washed for 15 minutes with water at 1 C. andfinally dried. The fabric was in the loose state during the wholetreatment. The dry fabric was moistened, heated, subjected to a knownmechanical compressive shrinking process on a mechanical compressingmachine set to a nominal compression rate of 2, 4 and 6% respectively,and then conditioned.

The wear testing yielded the following results:

The data given above was obtained by the following tests:

Abrasion resistance: Number of cycles in the warp direction, determinedwith the Stollflex apparatus described in Text. Res. Journal 19 (1949'),page 394.

Crease pattern value: Comparison with the crease pattern scale describedin SVF-Fachorgan 1.3 (195 8), page 247, determined after centrifugingthe test specimens. Optimum value: No. 5. When instead of beingcentrifuged the test specimens were drip-dried as recommended forso-called drip-dry materials the fabrics treated by the present processhad in all cases higher crease pattern values (shown in brackets in thetable).

Shrinkage: Determined after washing at C., drying, sprinkling to aweight increase of' and ironing (iron set for rayon).

Bursting pressure in kgJsq. crn 1000 weight per sq. in.

Bursting index:

A crease pattern value of 3 to 4 for a (drip-dried) calico fabric ofviscose fibres corresponds to a dressing with about 10% of aurea-formaldehyde or melamineformaldehyde condensation resin, but whensuch a dressing is applied the abrasion resistance of the treated fabricis much inferior to that of an untreated fabric. The abrasion resistanceof a fabric treated by the present process is in fact improved, and whenthe fabric is dripdried, its crease pattern value is better than thatwhich can be achieved by treatment with a resin. The shrinking tendencycan be reduced to a degree satisfying all demands by suitably settingthe degree of mechanical shrinking.

Example 11 This example illustrates the effect of tension applied duringthe treatment with ethylenediamine solution:

Two lengths of desized taffeta Weighing 98 g. per sq. m., consisting of44 filaments Ne 47/1 per centimetre in the warp and 28 identicalfilaments per centimetre in the weft, produced from viscose staplefibres of 1.5 deniers and having a staple length of 40 mm., wereimmersed for 30 seconds in an aqueous ethylenediarnine solution of 87%strength at 10 C., expressed on a laboratory-type padder, and kept for29.5 minutes at 20 C., during which time one length of fabric was leftin the loose state while the other was stretched on a stenter. The twolengths were then washed in the loose state in water at 10 C.,neutralised or acidulated with dilute acetic acid, again washed anddried without being stretched at 60 C.

After having been subsequently washed at 60 C., the fabric treatedwithout stretching was accorded a crease pattern value of 4 and awet-creasing angle of 118 (determined according to Monsanto, warpdirection, recovery Crease pattern value Resistance Shrinkage (percent)Percent fabric (Values in brackets for to abrasion indicates elongation)Bursting index swelling drip-dried specimens) Variant (see below) 1 wash25 washes 1 wash 25 washes 1 wash 25 1 Wash 25 1 wash 25 washes Washeswashes iv arp weft Warp welt Variant a: Variant b: Variant c: Variant(l: Variant e:

untreated, without compressive shrinkage.

treated with cthylcnerliarnine, without compressive shrinkage.

after minutes) while the stentered length was accorded the value 4 to 5and a wet oreasing angle of 124 C. A length of the identical fabric, nottreated with ethylenediamine, was accorded the crease pattern value 2 to3. The change in dimensions produced by the wash amounted in the case ofthe fabric treated in the loose state to +90% in the warp direction andto +32% in the weft direction; the corresponding figures for the fabrictreated with stretching were +7.6% and +12% respectively.

Example III This example illustrates the change produced by thetreatment with ethylenediamine on regenerated cellulose fibres ofdifferent nature. One length each of a taffeta fabric (weave asdescribed in Example '11) produced from conventional viscose staplefibres and Polynosic fibres was desized, dried, conditioned and thenimmersed for 30 seconds in an aqueous ethylenediamine solution of 78% byweight strength, expressed on a laboratoryty-pe padder to a weightincrease of 100%, fixed to a stente-r and together with it stored at 20C. in a sealed bag of polyethylene foil. After 29.5 minutes thespecimens were taken off the stenter and washed free fromethylenediamine, in the loose state, with tap water at The specimenswere expressed to a weight increase of 80%, dried for 1 hour at 60 C. ona stenter, and then subjected to a two-stage condensation process (forminutes at 105 C. and then for 5 minutes at 160 C.). To remove thecatalyst, the specimens were then washed at 40 C. and dried in stenteredstate at 60 C.

In the textile testing the viscose staple fibre fabric was accordedafter a machine wash at 60 C. (goods-to-liquor ratio 1:10) a creasepattern value of 45, and the Polynosic fabric a value of 5. Thedimensional change resulting from the wash amounted with conventionalviscose staple fabric, in the warp direction, to 5% and with Polynosicfabric 1.5%. Untreated control of conventional viscose staple fabricshowed a shrinkage of 7.5% in the warp direction when washed and driedunder identical conditions. The swelling values were 45-47% whichcompares with 80% for the untreated fabric.

Example I This example illustrates a combination of the treatments withethylenediamine, latex and resin. Desized lengths of the viscose taffetafabric used in Example {I were padded with an immersion time of 30sections with an ethylenediamine solution of 78% strength at C., keptfor 29.5 minutes on a stenter in a ventilated drying cabinet at 100 C.,then washed with cold water in the loose state, acidulated and then,without intermediate drying, impregnated with a polyacrylic ester latexcontaining free carboxyl groups (concentration 100 grams per litre,calculated as the dry content) in combination with 60 grams per litre ofa reactant resin of the type of the cyclic ethylene ureas (commercialproduct Resloom E50). The dressed specimens were dried on stenters at 60C. and then subjected to a two-stage condensation (for 15 minutes at 105C. and then for 5 minutes at 150 C.). A like treatment was applied tospecimens of the fabric treated with ethylene diamine but not with theresin and the latex.

The textile treating produced the following results: While the specimenstreated only with ethylenediamine, then washed and dried on a stenter,on subsequent washing at 60 C. shrunk in the warp direction by about 11%and in the weft direction by 3%, the specimens which had beenadditionally treated with the relatively very small amount of resindisplayed a satisfactory dimensional stability: after one wash theshrinkage in the warp and weft directions was 1.1% and 1.2% and after 10washes 2.0 and 1.5 respectively.

The specimens treated with ethylenediarnine but not with resin wereaccorded a crease pattern value of 5, and those treated withethylenediarnine, resin and latex corresponded to the crease patternvalve 4.

When specimens of the above fabric, without a preliminary ethylenediamine treatment, were treated with 2 /2 times the amount of resin,that is to say with 150 grams of Resloom E50 per litre and the identicalcontent of latex, with zinc nitrate as catalyst, their crease patternvalue was found to be 3-4, which was accompanied by a considerablediminution in the abrasion resistance.

This example thus shows clearly that the ethylenedia-mine treatmentcombined with a dressing with resin gives optimum results with an amountof resin that is much smaller than that required for producing finishesof the known kind, and at the same time the disadvantages involved inresin dressing are substantially prevented.

We claim:

1. A process for improving the wet crease resistance and for producing adrip-dry finish on a woven fabric of regenerated cellulose, whichcomprises immersing the fabric at 0 to 20 C., in the absence of anycatalyst, in an amount of an aqueous solution of ethylene diarnine of 70to strength by weight in excess of that which the fabric can take up,allowing aqueous solution of ethylene diamine to remain in contact withthe fabric for 3 to 30 minutes, removing the ethylene diamine from thefabric by washing with water and then drying the fabric.

2. A process for improving the wet crease resistance and for producing adrip-dry finish on a woven fabric of regenerated cellulose, whichcomprises immersing the fabric at 0 to 20 C., in the absence of anycatalyst, in an amount of an aqueous solution of ethylene diamine of 70to 90% strength by weight in excess of that which the fabric can takeup, removing the fabric from said solution and expressing excess aqueoussolution of ethylene di amine from the fabric, allowing the aqueoussolution of ethylene diamine adherent to the fabric which is not lessthan based on the weight of the initial fabric to remain in contact withthe fabric for a time suflicient to give a total time of contact betweenthe fabric and the aqueous solution of ethylene diamine of 3 to 30minutes, washing the fabric with water to remove ethylene diamine anddrying the fabric.

3. A process for improving the wet crease resistance and for producing adrip-dry finish on a woven fabric of regenerated cellulose, whichcomprises immersing the fabric at 0 to 20 C., in the absence of anycatalyst, in an amount of an aqueous solution of ethylene diamine of 70to 90% strength by weight in excess of that which the fabric can takeup, removing the fabric from said solution after a lapse of 0.5 to 5minutes and expressing excess aqueous solution of ethylene diamine fromthe fabric, allowing the aqueous solution of ethylene diamine adherentto the fabric which is not less than 100% based on the weight of theinitial fabric to remain in contact with the fabric for a timesufficient to give a total time of contact between the fabric and theaqueous solution of ethylene diarnine of 3 to 30 minutes, washing thefabric with water to remove ethylene diarnine and drying the fabric.

4. A process for improving the wet crease resistance and for producing adrip-dry finish on a Woven fabric of regenerated cellulose. whichcomprises immersing the fabric at 0 to 20 C., in the absence of anycatalyst, in an amount of an aqueous solution of ethylene diarnine of 70to 90% strength by weight in excess of that which the fabric can takeup, removing the fabric from said solution and expressing excess aqueoussolution of ethylene diamine from the fabric, allowing the aqueoussolution of ethylene diamine adherent to the fabric to remain in contactwith the fabric which is not less than 1% based on the weight of theinitial fabric for a time sufficient to give a total time of contactbetween the fabric and the aqueous solution of ethylene diamine of 3 to30 minutes, washing the fabric with water to remove ethylene diamine,drying the fabric and subjecting it to compressive shrinkage to improveits dimensional stability.

5. A process for improving the wet crease resistance and for producing adrip-dry finish on a woven fabric of regenerated cellulose, whichcomprises immersing the fabric at O to 20 C., in the absence of anycatalyst, in an amount of an aqueous solution of ethylene diamine of 70to 90% strength by weight in excess of that which the fabric can takeup, removing the fabric from said solution and expressing excess aqueoussolution of ethylene diamine from the fabric, allowing the aqueoussolution of ethylene diamine adherent to the fabric which is not lessthan 106% based on the weight of the initial fabric to remain in contactwith the fabric for a time sufficient to give a total time of contactbetween the fabric and the aqueous solution of ethylene diamine of 3 to30 minutes, washing the fabric with water to remove ethylene diamine,impregnating the fabric with formaldehyde, drying the fabric andcondensing the formaldehyde on the fabric, again washing with water anddrying, whereby swelling in water is reduced and the dry creaseresistance and dimensional stability of the fabric are improved.

6. A process for improving the wet crease resistance and for producing adrip-dry finish on a woven fabric of regenerated cellulose, whichcomprises immersing the fabric at to 20 C., in the absence of anycatalyst, in an amount of an aqueous solution of ethylene diamine of 70to 90% strength by weight in excess of that which the fabric can takeup, removing the fabric from said solution and expressing excess aqueoussolution of ethylene di mine from the fabric, allowing the aqueoussolution of ethylene diamine adherent to the fabric which is not lessthan 100% based on the weight of the initial fabric to remain in contactwith the fabric for a time sufficient to give a total time of contactbetween the fabric and the aqueous solution of ethylene diamine of 3 to30 minutes, washing the fabric with water to remove ethylene diamine,impregnating the fabric with a precondensate of a thermosettingamine-formaldehyde resin, drying the fabric and condensing theprecondensate on the fabric.

7. Process according to claim 6, comprising applying to the fabric anester of polyacrylic acid together with the resin precondensate.

8. A process for improving the wet crease resistance and for producing adrip'dry finish on a woven fabric of regenerated cellulose, whichcomprises immersing the fabric at 0 to 20 C., in the absence of anycatalyst, in an amount of an aqueous solution of ethylene diamine of tostrength by weight in excess of that which the fabric can take up,removing the fabric from said solution after a lapse of 0.5 to 5 minutesand expressing excess aqueous solution of ethylene diamine from thefabric which is to a weight increase of the fabric not less than basedon the weight of the initial fabric, allowing the aqueous solution ofethylene diamine adherent to the fabric to remain in contact with thefabric for a time sufficient to give a total time of contact between thefabric and the aqueous solution of ethylene diamine of 3 to 30 minutes,washing the fabric with water to remove ethylene diamine and drying thefabric.

References Cited in the file of this patent UNITED STATES PATENTS2,189,918 Moncrieff Feb. 13, 1940 FOREIGN PATENTS 479,341 Great BritainFeb. 3, 1938 750,088 Great Britain June 6, 1956 OTHER REFERENCES Trogus:Zeitschrift fur physikalische, Chemie, Part B, vol. 14, pp. 387-395(1931).

4. A PROCESS FOR IMPROVING THE WET CREASE RESISTANCE AND FOR PRODUCING ADRIP-DRY FINISH ON A WOVEN FABRIC OF REGENERATED CELLULOSE, WHICHCOMPRISES IMMERSING THE FABRIC AT 0 TO 20*C., IN THE ABSENCE OF ANYCATALYST, IN AN AMOUNT OF AN AQUEOUS SOLUTION OF ETHYLENE DIAMINE OF 70TO 90% STRENGTH BY WEIGHT IN EXCESS OF THAT WHICH THE FABRIC CAN TAKEUP, REMOVING THE FABRIC FROM SAID SOLUTION AND EXPRESSING EXCESS AQUEOUSSOLUTION OF ETHYLENE DIAMINE FROM THE FABRIC, ALLOWING THE AQUEOUSSOLUTION OF ETHYLENE DIAMINE ADHERENT TO THE FABRIC TO REMAIN IN CONTACTWITH THE FABRIC WHICH IS NOT LESS THAN 100% BASED ON THE WEIGHT OF THEINITIAL FABRIC FOR A TIME SUFFICIENT TO GIVE A TOTAL TIME OF CONTACTBETWEEN THE FABRIC AND THE AQUEOUS SOLUTION OF ETHYLENE DIAMINE OF 3 TO30 MINUTES, WASHING THE FARBIC WITH WATER TO REMOVE ETHYLENE DIAMINE,DRYING THE FABRIC AND SUBJECTING IT TO COMPRESSIVE SHRINKAGE TO IMPROVEITS DIMENSIONAL STABILITY.